Hydro-conversion reactions were carried out at 360°C under 5 MPa of H 2 pressure to study ring-opening reactions of 1-methyl naphthalene using NiMoS supported on γ-alumina and alumina-coated/mixed USY zeolites. The catalysts were characterized using N 2-BET, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), pyridine FT-IR, and high-resolution transmission electron microscopy (HRTEM) to study the influence of morphological and acidic properties on hydrogenation (HYD) and hydrocracking (HC) reactions. NMACZ-2 (NiMoS supported on the minimum amount of alumina-coated USY zeolite) showed enhanced reactivity for HC and produced (alkyl)benzenes with the highest yield, of ca. 80%. By-products were tetralin, decalin and cyclo-paraffin species. The tetralin species produced using NMACZ-2 moved into the alumina-coated USY zeolite support before undergoing HYD to produce decalin species, which were rapidly and selectively hydro-cracked into (alkyl)benzenes. A large amount of decalin was produced through the HYD of tetralin without significant cracking, possibly due to the weak acid character of γ-alumina. Bulk-phase Mo oxide species on NMAZ (physical mixture of alumina and USY zeolite), as well as deactivation of the catalysts due to coke formation over the naked zeolite surface, inhibited the ring opening of tetralin, decreasing the yield of (alkyl) benzene. 3 Various morphologies, such as the MoS 2 structure and acidic characteristics of the catalysts, were crucial factors affecting the HC reactivity of 1-methyl naphthalene.

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Alumina-silica-supported NiMoS composites were examined in single-and dual-layer catalyst beds in a high-pressure (5 MPa) flow reactor to achieve ultra low sulfur (10 ppm) diesel fuels. Three types of alumina-silica composite supports were prepared by co-precipitation to control the particle size and arrangement of alumina and silica. SiO 2 content influenced the catalytic performance, and the maximum conversion was ~27%, regardless of the preparation conditions. Alumina crystal size controlled the acidity and surface area of the support, key factors influencing catalytic performance. NiMoASA-2(27), prepared by procedure 2, achieved 4.5 and 3 ppm S at 345 and 360°C, respectively, in the single bed reactor at a liquid hourly space velocity (LHSV) of 1 h-1. NiMoASA-2(27) achieved the best performance of the supports examined in this study. The double-layer catalyst bed contained commercial CoMoS (LX6) and NiMoASA-2(27) in the first and the second beds at 345 and 360°C, respectively, and achieved 5 and 2 ppm S, indicating better performance at higher temperatures. The reaction order for the hydrodesulfurization (HDS) of refractory sulfur species was close to unity over NiMoASA-2(27), which was significantly higher than that of the commercial CoMoS catalyst. Alumina-silica-supported NiMoS in the second bed of the dual-layer catalyst bed achieved less than 10 ppm S for refractory sulfur species with ~500 ppm S.

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